Apparatus for finishing bearing surfaces



Jan- 26, 1937- H. c. SATTERTHWAITE 2,069,099

APPARATUS FOR FINISHING BEARING SURFACES Filed Feb. 4, 1935 5Sheets-Sheet 1 ill FIG.3. l

HAY C. SATTERTHWAITE ATTORNEYS Jan. 26, 1937. H. c. sA'rTERTHwAlTE2,069,099

APPARATUS FOR FINISHING 'BEARING SURFACES Filed Feb. 4, 1935 3Sheets-Sheet 2 INVENTOR .lll

lll

HARRY C.SATTERrHwA|TE w K mw ww @w WN//w Jan. 26,1937. H. c.sATTERTHwAlTE 2,059,099

APPARATUS FOR FINISHING BEARING SURFACES Filed Feb. 4, 1935 3Sheets-Sheet 3 ATTORNEY 5 estaras 2e ies? y Zd unirse 4stairs garantortica APPARATUSFOR FINISHING BEARING SURFACES Harry C. Satterthwaite,Southfield Township, Oakland County, Mich., assgnor to CogsdillManufacturing Company, Inc., Detroit, meh., a' corporation of MichiganApplication February 4, 19?5, Serial No. 4,960 15 Claims. (Cl. 2.9-33)This invention relates to improvements in ap- 'surface ofthe work so asto effect a slight peenparatus for finishing surfaces of various shapesing action of the rolls on the surface each time including, vertical,tapered, and curved bearing the former are reengaged with the latter.The

surfaces. feature of periodically releasing the processing One of theprincipal objects of this invention rolls from engagement with thesurface of the 5 resides in the provision of a relatively simple work isparticularly advantageous in a construcmethod for processing a metallicwork piece tion wherein the rolls and the portion of the rendering itpossible to impart a smoother, more revoluble arbor supporting the rollsare oppoaccurate and denser surface to the portion of sitely tapered toeffect the desired radial adthe work acted upon irrespective of whetherthe justment of the rolls, since in such construc- 10 surface iscylindrical. radial, tapered or curved. tions the ends of the rollsengaging the portion The present invention contemplates imparting ofmthearbor of greatest diameter hav a higher a smoother and more accuratesurface to ythe peripheral speed than the ends of the rolls en- `workpiece by. subjecting the surface to comgaging the portion of the arborof less diameter 1 151 b'ined rolling and sliding pressures determinedand, as a consequence, there is a tendency for 15 in dependence upon thestructure ofthe material the rolls to slide along the surface as long asforming the surface and, in addition, contemthe rolls are maintainedunder pressure in conplates increasing the density of the surface bytact with the surface. However, by periodically peening the latter, orby subjecting the same to relieving the contacting pressure between thea successive series of impacts. l processing rolls and the surface ofthe work, 20

Another object of this invention resides in the rotation of the rollsrelative to the surface is provision of apparatus for carrying out theinsured and dierent portions of the rolls will be method previouslyreferred to, having a series brought into contact with the surfaceduring of processing rolls mounted in a cage permitting the finishingoperation.

relative angular displacement of the rolls with Still another feature ofthe present invention 25 respect to the cage. 'Ihis angular displacementresides in the provision of a processing tool havof the processing rollsis highly desirable, since ing an arbor provided with a tapered portionit permits imparting the aforesaid sliding presfor supporting aplurality of sets of processing sure to the surface during the rollingoperation rolls, and having means for independently adand thereby offersthe possibility of obtaining justing the sets of rolls axially of thearbor to 30 a smoother, more accurate surface than if the vary thediameter of the several series of rolls. axes of the rolls were fixed.In addition to the foregoing, the present in- Another advantageousfeature of this invenvention contemplates apparatus for processing tionresides in the provision of apparatus of the surfaces irrespective ofthe particular contour above type, wherein the support for the procofthe latter and this feature as well as the fore- 35 essing rolls isfashioned to periodically force going objects will be made more apparentas the latter against the surface to be processed so this descriptionproceeds, especially when conas to peen this surface and therebyincrease the sidered in connection with the accompanying density yof thesame. drawings, wherein:

40 Still another object of the present invention Figure 1 is a sideelevational view of a process- 40 consists in the provision of aprocessing tool ing tool constructed in accordance with this inj'havingfinishing rolls normally arranged in a vention;

position wherein-the outside diameter thereof is Figure 2 is alongitudinal sectional view sumcientlyless than the internal diameter ofthe through the tool shown in Figure 1;

bore to be processed to permit freely inserting Figure 3 is afragmentary View similar to Fig- 45 the rolls in the bore and, inaddition, having ure 1 showing a modified form of processing meansoperable in dependence upon inserting tool; y 4 the processing rollsinto the bore to expand the Figure 4 is a longitudinal sectional viewlatter rolls into engagement with the internal through the constructionshown in Figure 3;

surface of the bore. Figure 5 is a side elevational view of another 5o Afurther advantageous feature of this invenembodiment of this invention;tion consists .in the provision of a processing Figures 6 and 7 arerespectively cross sectional tool of the type set forth in the precedingparaviews taken on the lines 6-6 and 1 1 of Fig- "f'graph `having meansfor periodically releasing ure 5; the processing rolls from engagementwith the Figure 8 is a longitudinal sectional view 55 through stillanother modied form of processing tool;

Figure 9 is a cross sectional view taken on the line 9--9 of Figure 8;

Figure 10 is a side elevational view of still another modification;

Figure 11 is a longitudinal sectional view through a further modifiedform of processing tool; and l Figure 12 is an end elevational view ofthe construction shown in Figure 1l.

Referring now to the drawings and with special reference to theembodiment of the invention featured in Figures 1 and 2, it will benoted that the reference character l5 designates a processing toolhaving a revoluble arbor I8 provided with a tapered end portion I1adapted to support two sets of processing rolls I3 and I9. In thepresent instance, both sets of processing rolls are tapered from end toend to a degree corresponding to the degree of taper of the portion I1of the arbor, but in an opposite direction from the latter taper so as.to permit the same to size or finish truly cylindrical surfaces. Theseries of processing rolls I3 are held in assembled relation to eachother by means of an annular cage 20 provided with circumferentiallyspaced slots 2l corresponding in number to the number of rolls I8, andeach slot having the opposed side walls tapered to a degreecorresponding to the taper of the rolls i8. The width of each of theslots 2l throughout the length thereof is greater than the diameter ofthe rolls I8 so as to permit the angular movement of the rolls in thecage 20 desired to eiect the sliding pressure upon the surface to beprocessed. As shown in Figure i, the forward-ends of the slots 2t arepreferably open to receive the rolls iii, and axial displacement of thelatter relative 'to the cage during use. is prevented by means of anadjustable collar 22.

The series of rolls l@ are held in assembled relation by a cage 23identical in construction to the cage 20 and having the rear endabutting vthe front side 'of the adjustable collar 22. The rolls i9 areprevented from axial displacement relative to the cage 23 by means of awasher 26 engaging the forward end of the cage and slidably supportedupon a rod 25 extending axially through the tapered portion il of thearbor to a position in the counterbored portion 26 of the arbor in rearof the said tapered portion.. The forward end of the rod projects beyondthe washer 24 and is threaded for engagement with an adjusting nut 28normally securedy against accidental movement with respect to the rod bymeans of a set screw 29 and adapted to act upon the washer 24 to movethe same axially of the arbor through the medium of a thrust bearing Therod 25 is held from rotation relative to the arbor i6 by means of atransverse pin 3l carried by the rear end of the rod for movementtherewith and having the opposite ends projecting through elongatedslots 32 formed in the arbor so as to permit shifting the rod axially ofthe arbor. The extremities of the pin 3i are secured in a collar 33mounted upon the arbor in rear of the tapered portion I1 adjacent asecond collar 34 freely mounted upon the arbor I6 and forming anabutment for the rear end of the cage 2G. Inasmuch as the collar 33rotates as a unit with the arbor relative to the collar 34, a suitablethrust bearing 36 is interposed between these collars and the collar 34is normally yieldably urged into abutting relation with von the arbor tovary the space between the forward end of the sleeve and the rear facecollar.33.

The advantage of this adjustment will be apparent when it is consideredthat both sets of of the 'processing rolls are initially so positionedupon the tapered portion Il of the arbor that the external diameter ofthe rolls is less than the internal diameter of the work-piece to befinished in order to permit the tool to be readily inserted into thework. Accordingly, the width of the aforesaid space between the forwardend of the sleeve 38 on the abutment 31 and the collar 33 ispredetermined so that movement of the collar rearwardly into engagementwith the forward end of the sleeve 38 expands both series of rolls tothe proper diameters required to engage the rolls with the internalsurface of the work to be nished. In the present instance, the collar ismoved rearwardly the extent permitted by the width of the space byengagement of the rear end of the work with the iront face ofthe collar3e or, in other words, the rolls are expanded to the required diametersby the work` to be processed. 'it will, oi? course, be apparent that theextent of expansion of the rolls depends upon the degree of axialrearward displacement of the rolls relative to the tapered portion il ofthe arbor, and that the ultimate diameter of both series of rolls may bevaried by adjusting the abutment 3l to vary the space between theierward end of the sleeve 35 and rear face of the collar 33. Attentionmay be called to the fact at this point, that merely adjusting theabutment 3i axially of the arbor results in correspondingly varying theoutside diameters of both sets of processing rolls and in order toindependently vary the outside diameters of both sets of rolls the spacebetween these sets of rolls must be varied. This is accomplished hereinby interposing the adjustable collar 23 between the two sets ofprocessing rolls and, as shown in Figure 2. this collar comprises a pairof cooperating sections having the adjacent faces serrated and inclinedto a plane perpendicular to the axis of the arbor. With this latterconstruction, it will be apparent that the diameters of the two sets oirolls may be varied by mereiy loosening the adjusting nut 28 andrelatively rotating the cooperating sections of the collar in onedirection or the otherr depending upon whether it is desired to decreaseor increase the space between the two series of rolls. Of course,varying the space between the two sets oi rolls changes the relativepositions of these rolls axially with respect to the tapered portion I1of the arbor and thereby provides for changing the diameter of one setof rolls relative to the diameter of the other set.

Although a tool constructed in accordance with the foregoing willprovide for subjecting the surface of the work to rolling and slidingpresbearing 35, previously described, may be omitted be desired to peenthe surface during the rolling operation. This may be accomplished inthe embodiment of the invention described above, by providingcircumferentially spaced axially extending cams 39 on the taperedsurface of the portion I1 of the processing tool, so that the rolls willbe periodically forced outwardly into engagement with the surface to befinished.

As previously stated, the desired peening action of the processing rollson the surface of the work may be secured by periodically relieving thepressure oi. engagement of the processing rolls with said surface, andone method of accomplishing this result is shown in the embodiment ofthe invention disclosed in Figures 3 and 4.

This embodiment of the invention differs from the one previouslydescribed in that the collar' 33' is xed against rotation with the arborI6', but is permitted to slide axially with respect to this arbor, inthe manner designated by the reference character 40. Consequently, thethrust and in the present instance the adjacent radial surfaces of thetwo collars 33' and 34' are fashioned to form cooperating cam faces inthe manner shown in Figure 3.-

In the present embodiment of the invention the extremities of thetransverse pin 3|' carried by the rear end of the 'rod 25 extend intothe collar 34 so that the latter collar rotates as a unit with the arborI6', and is also capable of a limited axial movement relative to thearbor due to the elongated slots 32 through which the transverse pinextends. With the above construction it will be apparent that as thearbor I 5' is rotated, the cam face on the Acollar 34' cooperates withthe correspondingly cammed face on the collar 33 to periodically movethe collar- 34 forwardly and thereby contract or reduce the outsidediameters of the two sets of processing rolls. It will, of course, beapparent that the same results can be obtained by holding the collarstationary and axially moving the arbor relative thereto. The foregoingconstruction, in addition to providing the desirable peening action,also insures moving different por-- tions of the processing rolls intocontact with the surface of the work during the rolling operation.

In Figure 5 of the drawings, I have shown a rotary processing toolhaving provision for iinishing a surface extending radially with respectto the axis of rotation and having means for simultaneously finishing asurface concentric with respect to the axis of rotation. In detail, thetool shown in Figure 5 comprises two sets of processing rolls 4I and 42supported upon a rotatable arbor 43 in axial spaced relation to eachother. The series of processing rolls 4I\ are held in assembledrelationship by means of a cage 44 having a plurality ofcircumferentially spaced axially extending slots 45 open at the forwardend of the cage to permit inserting the rolls into the same. As in thefirst described form of the invention, the slots 45 are of sucient widthto provide limited angular displacement of the processing rolls relativeto the cage and this is desirable, since it affords the combined slidingand rolling action previously re,

ferred to. In the event it is desired to incorporate the peeningfunction during the rolling operation, the portion ofthe arborsupporting the rolls 4| may be provided with circumferentially spaceddepressions, which as shown, are the flats 46 extending axially of thearbor and operable to periodically force the processing rolls outwardlyto effect a blow against the surface being rolled.

The processing rolls 45 are held against axial displacement relative tothe cage 44 by means of a spacer 41 sleeved upon the arbor in advance ofthe cage 44 and engageable with the front end of the latter in themanner shown in Figure 5. The forward end of the spacer has an abutmentfor the rear end of the cage 43 similar to the construction of the cage44 and operable to hold' the processing rolls 42 in assembledrelationship. The slots 49 in the cage 43 are suilciently wider than thediameter of the processing rolls 42 to provide the angular displacementof the rolls previously referred to, and the open ends of the slots arenormally closed by means of a collar 50 held in assembled relationuponthe arbor by a nut 5I threaded upon the forward end of the 'Ihearbor 43 is provided with an enlarged por- -tion 52 at a pointv spacedrearwardly from the 'ya hub 56 supported on the arbor in spaced relationto the cage 44 by means of a spacer 51 and having a series of radiallyextending slots open at the outer ends to permit inserting theprocessing rolls 54 into the cage. The width of the slots is preferablygreater thanl the diameter of the processing rolls to aord angulardisplacement of the latter during the rolling operation and,l if

desired, the front face of the spacer 53 may be provided with a seriesof radially extending projections for periodically forcing theprocessing rolls 54 to effect a blow against the surface being rolled,VVin the same manner as described above. In the present instance, therolls 54 are held from outward displacement with respect to the cage 55by means of a sleeve 53 having the rear end secured to the arbor andhaving the forward end lsleeved over the enlargement 52, spacer 53, andperiphery of the cage 55. A tool 'constructed in accordance with theforegoing renders it possible to not only roll the internal annularsurface of a work piece, but at the same time provides for nishing oneend of the work piece.

The tools previously described arev particularly designed to finish theinternal annular surface of a bore, and in order toillustrate that theprinci- 4ples of the present invention are equally appli.

cable for nishing external annular surfaces, reference will now be madeto Figures 8 and 9. In Figure 8, the work piece having the externalsurface to be finished is designated by the reference character 60 andthe processing tool is indicated generally by the reference character6I. In detail, the processing tool comprises a revoluble head 62embodying two axially spaced sets of processing rolls 63 and 64. Thecage for the rear processing rolls 63 is designated by the referencecharacter 65 and is sleeved within a collar 68 which in turn is securedin the rear portion of the rotatable head 62 by means of the tap screw61. The cage 65 is secured against rearward axial displacement withrespect to the collar 66 by means of an insert EB-and the forwardportion of the cage is provided with a plurality of slots 69 open at thefront ends to receive the rolls 63. Displacement of the rolls axiallyforwardly with respect to the cage 65 is prevented by a ring 10 snappedinto a counterbored portion of the collar at the front side thereofinraccordance with conventional practice. As in all of the foregoingembodiments of the invention, each of the slots 89 is greater in widththroughout the length thereof than the diameter of the rolls so as topermit the desired angular displacement of the rolls relative to thecage during the rolling operation. In addition, the internal surface ofthe collar 66 engaging the rolls is fashioned to provide a plurality ofcams 'Il operable to periodically force the rolls inwardly to eect ablow upon the surface of the work during the rolling operation. rThefront set of processing rolls M are maintained in spaced relation withrespect to the rear set of processing rolls by means of a spacer l2, andthe construction associated with the former set of rolls is identical tothe construction previously described in connection with 0 the rearsetof rolls.

Due to the fact that the surfaces of the valve seats of an internalcombustion engine, for example, must be extremely accurate in order tosecure eiilcient operation I propose to flnish sur- 5 faces of thischaracter by a processing tool constructed in accordance with thisinvention. The

tool shown in Figure l0 is particularly designed l :5 a series ofprocessing rolls 83 held in assembled relationship by means of a cage 84positioned at the forward end against an enlargement 85 on the pilot 8|,The cage 84 is provided with a plurality of slots 86 corresponding innumber to 0 the number of rolls and open at the outer ends to receivethe rolls. The slots 86 are wider than the diameter of the rolls so asto provide the angular displacement of the rolls required to secure thecombined rolling and sliding action and, if desired. the frustoconicalsurface 82 may be provided with a plurality of cams similar to the camsll for periodically forcing the rolls outwardly to effect a blow on thesurface during the rolling operation. The rolls are held in assem- 0bled relation within the slots by means of a collar 3T secured tothearbor and having a portion receiving the rear end of the cage in themanner clearly shown in Figure 10.

All of the tools previously described have been 55 restricted in theiruse to finishing true surfaces,

and accordingly, I have illustrated in Figures 1l and l2 a processingtool capable of finishing curved surfaces. In detail, the processingtool in Figure 1l is provided with a rotatable arbor 90 having a portion9i at the forward end providing, ineifect, a prolate spheroidal surface92 forming a support for the rolls 93 which are curved about their majoraxes in the manner shown in Figure 11. The rolls 93 are supported in acage 94 secured to the extreme front end of the arbor by means of a nut95 threaded upon the arbor and, in addition, having slots 98 forreceiving the rolls 93. The slots 96 are of sumcient dimension to affordthe angular displacement of the rolls 93 required to effect the combinedrolling and sliding action and, also in this instance, the prolatespheroidal surface 92 Vmay be provided with cams in the event it is 5desired to periodically force the rolls 93 outspaanse wardly to eect ablow on the surface of the work being rolled. A

Thus from the foregoing it will be observed that the present inventioncontemplates processing surfaces of numerous different types and, as aconsequence, possesses a greater application than processing toolsheretofore produced. It will also be apparent that in each of theseveral embodiments of the invention selected herein for the purpose ofillustration, the processing rolls are supported in such a manner as topermit angular displacement of the rolls relative to the retainertherefor, so that the surface being processed will besubjected tocombined rolling and sliding pressures.v In addition, each of theseveral embodiments of the invention offers the possibility of impartinga. successive series of impacts to the surface being processed, duringthe rolling operation, and this feature is desirable in many instances,since it provides for increasing the density of the metal forming thesurface being finished.

What I claim as my invention is:

1. A work processing toolcomprising a revoluble member having a taperedannular surface,

vrotatable processing rolls supported upon said surface andcorrespondingly tapered in an opposite direction to provide forprocessing cylindrical surfaces, means for moving the rolls intoengagement with the cylindrical surface of the work to be processed, andmeans operable in dependence upon rotation of the revoluble member toperiodically reciprocate the rolls axially of the tapered surface.

2. A. .work processing tool comprising a revoluble member having atapered annular surface extending in the direction of the axis ofrotation of said member, rotatable processing rolls supported upon saidsurface, means for retaining the rolls in assembled relationshipincluding a retainer, and means operable in dependence upon rotation ofthe revoluble member for moving the rolls axially of the tapered surfacein a direction to relieve the pressure of engagement of the rolls withthe surface of the work being processed.

3. A work processing tool comprising a revoluble member having a taperedannular surface extending in the direction of the axis of rotation ofsaid member, rotatable processing rolls supported upon the taperedsurface for engagement with the surface of the work to be processed,means for retaining the rolls in assembled relationship providinglimited angular displacement of the rolls relative to the surface of thework being processed, and means operable in dependence upon rotation ofsaid member to periodically move the rolls axially of the taperedsurface in a direction to relieve the pressure of engzliigement of therolls with the surface of the wor 4. A work processing tool comprising arevoluble member having a tapered annular surface extending in thedirection of the axis of said member, rotatable processing rollssupported upon the tapered surface and insertable into a bore of thework having a surface to be processed, means for retaining theprocessing rolls in assembled relationship providing angulardisplacement of the rolls relative to the surface aforesaid of the work,means operable in dependence upon inserting the processing rolls intothe bore for expanding the rolls into contact with the surface of thebore to be processed, and means operable in dependence upon rotation of4the revoluble member for periodically moving the rolls axially of thetapered surface on said member in a direction to permit movement of therolls inwardly with respect to the surface aforesaid of the bore.

5. A work processing tool comprising a revoluble member having a taperedannular surface extending in the direction of the axis of the revolublemember, two sets of rotatable processing rolls supported upon thetapered surface of said member in axial spaced relationship and beingcorrespondingly tapered in a direction opposite to the taper of saidsurface, and a spacer interposed between the two sets of processingrolls adjustable to vary the space therebetween.

6. A work processing tool comprising a revoluble member having a.surface extending radially with respect to the axis of rotation thereof,a series of rotatable processing rolls having their axes also extendingradially with respect to the axis of rotation of the member andsupported against the surface Aaforesaid for engagement with a radialsurface on the work to be processed, and means for retaining theprocessing Arolls in assembled relationshipproviding limited angulardisplacement'of the rolls relative to the radial surface of the work tobe processed.

7. A work processing tool comprising a revolublev member having anaxially extending pprtion and having a portion extending radially withrespect to the axis of rotation thereof, rotatable processing rollssupported on the axially extending portion for engagement with onesurface of the work to be processed, a second series of rotatableprocessing rolls extending radially with respect to the axis of rotationand supported in engagement with the radial surface of said member, andretainers for holding the two sets of processing rolls in assembledrelationship and providing Yangular displacement of the rolls withrespect to the surfaces of the work -engaged thereby.

8. A work processing tool comprising a revoluble member having an4annular portion for receiving the work having .a surface to beprocessed, rotatable processing rolls for engagement with the lexternalsurface of the work to be processed, and means supporting the processingrolls in the annular portion of the rotatable member in circumferentialspaced relationship around the work including aretainer 'providing forcircumferential angular displacement of the rolls across the surface ofthe work to impart combined rolling and sliding pressures to saidsurface.

9. A work processing tool comprisingl a revoluble member having aspheroidal surface, rotatable processing rolls having their externalsurfaces curved with respect to the major -axes thereof to correspondwith the spheroidal surface aforesaid on` the member and engageablewith. a similar surface of the work to be processed, and means forretaining they rolls in circumferential spaced relationship around thespheroidal surface and permitting angular displacement of the rollsacross said surface during the processing operation to impart combinedrolling and sliding pressures on said surface.

10. A work processing tool comprising a revoluble member having a'frustoconical suro face,- rotatable p rolls supported upon said surfacefor engagement with the surface of the work to be processed, means forretaining the rolls in assembled relationship, and means forperiodically relatively moving the rolls and revoluble member axially ina direction to relieve the pressure of engagement of the rolls with thesurface of the work being processed.

1l. A work processing tool comprising a revoluble member having afrustoconicalsurface, rotatable processing rolls supported upon thesurface for engagement with the surface of the Work to be processed,means for retaining the rolls in assembled relationship, and meansoperable in dependence upon rotation of the revoluble member toperiodically relatively move said member and rolls in an axial directionto relieve the pressure of engagement of the rolls with the surface ofthe work being processed.

l2. A workv processing tool comprising a revoluble member having atapered surface, rotatable processing rolls supported upon said surfaceand correspondingly tapered in an opposite direction to provide forprocessing cylindrical surfaces, means for moving the rolls intoengagement with the cylindrical surface of the work to be processed andmeans for periodically relatively reciprocating the revoluble member androlls.

13. A work processing tool comprising a revoluble member having asurface extending outwardly with respect to .'the axis of rotationthereof, a series of rotatable processing rolls having their axes alsoextending outwardly with respect to the axis of rotation of the memberand supported against the surface aforesaid for engagement with thecorresponding surface 'of the work to be processed, means for retainingthe processing rolls in assembled relationship providing limited angulardisplacement of the rolls relative to the surf/ace of the work to beprocessed, and means for periodically relieving the pressure ofengagement of the rolls with said surface. A

14. A work processing tool comprising a revoluble member having anannular portion for receiving the work, rotatable processing rollsengageable with the external surface of the work to be processed, meansfor supporting the processing rolls in the annular portion of therotatable member permitting angular displacement of the rolls relativeto the surface of the work to be processed, and cam means forperiodically urging the rolls into engagement with the surface of thework and for relieving'the pressure ofJengagement of the rolls with thesurface of the work.

l5. A work processing tool comprising a revoluble member having asurface extending outwardly with respect to the axis of rotation of saidmember, a series of rotatable processing rolls having their axes alsoextending outwardly with respect to the axis of rotation of said memberand supported against the outwardly extending surface for engagementwith the surface of the work to be processed, and means for retainingthe processing rolls in circumferential spaced relationship andproviding forl limited angular displacement of the rolls across thesurface of the work to be processed to impart combined rolling andsliding pressures to the latter surface.

` HARRY c. sA'I'rER'mwArI'E.

